The present invention generally relates to a fiber guide and, in particular, relates to such a fiber guide having an adjustable fiber aperture.
In many instances, when a fiber is wound upon a mandrel, for example, optical fibers are wound upon mandrels and used as a communication link between a control station and a projectile, some form of an adhesive is applied to the fiber to ensure that the windings upon the mandrel are retained in the proper disposition.
At the present time, the adhesive is usually applied by either one of two different techniques. One technique is to apply, generally by spraying, adhesive after each layer of fiber is wound. For example, when each layer of optical fiber is completed, the adhesive is sprayed upon that layer. Hence, in this technique, the optical fiber is wound without adhesive and the spraying of the previous layer contributes to the position retention of the subsequent layer. The spraying technique has numerous drawbacks. In particular, the mandrel, and hence the winding process, is stopped after each layer is wound so that the adhesive can be sprayed on the exposed layer. The mandrel is then incrementally rotated to apply the adhesive completely upon the layer. Thus, the winding time of a given mandrel is extended due to the need for the stopping and incrementing. Another drawback of this technique is that, regardless of various safeguards, the adhesive is difficult to apply uniformly both along and between each layer. Thus, when being unwound, the optical fiber may not unwind smoothly and become damaged due to the differing adhesive forces along the entire length thereof.
Another technique for applying an adhesive to a fiber being wound upon a mandrel is, effectively, both pressureless and continuous. These types of techniques substantially overcome the drawbacks of the spraying techniques. However, other difficulties are encountered. For example, the optical fiber, once winding has begun, cannot be removed without breakage or considerable difficulty. For example, if a flaw is found in the optical fiber being wound it may have to be returned to the manufacturer for repair. As another example, since the adhesive is applied prior to the actual winding, if the winding is interrupted the adhesive will dry and the optical fiber can become glued in the winding mechanisms. Currently, the more common apparatus utilizing this adhesive application technique include fiber guides that can be characterized as the tube/needle or the split die.
In the tube/needle fiber guide, the optical fiber is threaded through the end of a needle that traps and guides the optical fiber. Consequently, in order to remove the optical fiber, the optical fiber must either be broken or completely drawn through the needle opening. If the optical fiber is broke the fiber must thereafter be spliced and thus, the communication and/or strength characteristics thereof can be significantly reduced. If the optical fiber is drawn through the needle a substantial amount of waste can occur. Further, the needle of such an arrangement has a fixed opening and thus different apparatus are required for different sizes of optical fiber.
In the split die fiber guide the optical fiber is secured between the members of the die and drawn therethrough. However, the die assembly must be disassembled every time the optical fiber is to be removed or the winding process interrupted for an extended length of time. Further, the split die has a fixed opening and thus, different dies are required for different sizes of optical fiber.
Thus, a fiber guide is needed that not only allows removal of the fiber, without difficulty or detriment thereto, at any time and enhances uniform adhesive application but also includes an adjustable aperture to better compensate for variations in fiber size.